Bicycle

ABSTRACT

The basic principle of the invention consists in a mechanical adjusting device comprising at least one double-acting piston/cylinder assembly which can be extended “automatically”.

DESCRIPTION

[0001] The present invention relates to a bicycle according to thepreambles of one of claims 1, 30 and 47.

[0002] Such a bicycle is known from WO 99/03721. The bicycle describedthere comprises a pneumatically sprung front fork with two fork arms aswell as a pneumatically sprung rear-wheel suspension, each being formedby double-acting pneumatic cylinders. A piston positioned inside thecylinder divides each of the pneumatic cylinders into a first cylinderchamber and a second cylinder chamber. The first cylinder chamber formsa first gas-pressurized spring and counteracts a “springing in” of thefork or of the rear-wheel suspension, respectively, and the secondcylinder chamber forms a second gas-pressurized spring that counteractsa “springing out”. The pneumatic cylinders each comprise valves for theseparate filling or ventilating, respectively, of the first and secondcylinder chambers, which enables a length adjustment or a variation ofthe “spring strength”, respectively.

[0003] DE 298 10 431 U1 discloses a so-called mountain bike that is inparticular suited for riding on hilly ground. It comprises a sprungfront fork with telescopic fork arms, the length of which is adjustablein steps. Each fork arm comprises a locking pin for fixing the adjusted“fork length” or “fork height”, respectively. In the interior of thetelescopic fork arms, a helical spring is positioned which at leastpartially buffers shocks that are introduced via the front wheel, andthus improves the riding comfort. The rear wheel is mounted on a swingarm rear suspension that is pivotable around the pedal bearing axis andthat is supported toward the frame by a shock-absorbing leg that takesup pressure forces. The shock-absorbing leg is fastened to the frame bymeans of quick release means, with several “fastening points” beingprovided, which enables a step-wise adjustment of the angle between theswing arm rear suspension and the frame, i.e. a step-wise “heightadjustment” of the rear wheel. Due to the individual “adjustability inheight” of the front wheel suspension and the rear wheel suspension, anapproximately horizontal sitting position can be adjusted both whenriding uphill and when riding downhill. It is of advantage in particularwhen riding downhill that the front wheel is “extended” and the rearwheel is “retracted” since this causes the center of gravity to betransferred backwards and the risk of overturning on actuation of thefront wheel brake to be reduced. Furthermore, it is of advantage whenriding uphill that the front spring element is retracted and the rearone is extended in order to transfer the cyclist's center of gravityfurther to the front. The cyclist thus takes up a more relaxed positionwhich increases the efficiency when riding uphill.

[0004] DE 41 01 745 A1 discloses a bicycle with a sprung swing arm rearsuspension that is connected with the bicycle frame via a resilientspring element, wherein a locking device comprising a cable pull isprovided for locking the suspension.

[0005] U.S. Pat. No. 6,044,940, U.S. Pat. No. 2,115,072, and U.S. Pat.No. 4,159,105 disclose pneumatic or hydraulic piston/cylinder assembliesthat are used as spring or damping elements, respectively.

[0006] Furthermore, DE 198 55 161 C1 discloses a height adjusting devicecomprising a tension spring for adjusting the height of a seat pillar ofa bicycle.

[0007] U.S. Pat. No. 5,086,866 discloses an off-road motorcycle, whereinthe front-wheel and the rear-wheel suspensions can be adjusted in heightby means of a hydraulic lifting device, with a pressure generatingdevice being provided for generating a hydraulic pressure. The heightadjustment of the front-wheel suspension and the rear-wheel suspensionis performed simultaneously, so that the frame remains in asubstantially horizontally orientated.

[0008] U.S. Pat. No. 4,735,276 discloses a racing motorcycle comprisinga front fork that is pneumatically adjustable in height, wherein thefork is completely lowered prior to the start so as to avoid taking offof the front wheel during the starting phase. During riding, the frontwheel is pneumatically extended to normal height.

[0009] It is an object of the present invention to provide amulti-purpose adjusting device that can be adjusted easily andcomfortably, in particular for adjusting the height of the front-wheelsuspension, the rear-wheel suspension, the saddle or the steering stem,respectively, of a bicycle.

[0010] This object is solved by the features of claims 1, 30 and 47.Advantageous embodiments and further developments of the invention maybe taken from the subclaims.

[0011] The basic principle of the invention consists in a mechanicaladjusting device comprising at least one double-acting piston/cylinderassembly which can be extended “automatically”.

[0012] In a first basic variant of the invention, at least two adjustingdevices are provided, e.g. the height adjusting devices of thefront-wheel suspension and of the rear-wheel suspension, which arecoupled such that the rear wheel is “automatically extended” when thefront wheel is “retracted”, and vice versa.

[0013] The adjusting devices for the height adjustment of thefront-wheel and rear-wheel suspensions each comprise at least onedouble-acting piston/cylinder assembly with respective “plus chambers”and “minus chambers” which are coupled via pressurizing medium lines andat least one shut-off device. For adjusting the riding inclination, theshut-off device is opened. By pressing down the handle bar or by weighttransfer of the cyclist, respectively, the piston/cylinder assembly ofthe front wheel is retracted, this causing the “front wheel height” tobe reduced and the piston/cylinder assembly of the rear wheel to beextended. Pressurizing medium thus flows from the plus chamber of the“front” piston/cylinder assembly to the plus chamber of the “rear”piston/cylinder assembly and from the minus chamber of the rearpiston/cylinder assembly to the minus chamber of the front one. The“plus circuit” and the “minus circuit” may have approximately equalpressures.

[0014] Vice versa, by pressing down the frame in the rear section, thepiston/cylinder assembly of the rear wheel can be retracted and thepiston/cylinder assembly of the front wheel can be extended, thiselongating the front fork and the range of spring. After the adjustmenthas been effected, the shut-off device will be closed again.

[0015] According to a further development of the invention, thepiston/cylinder assemblies and the pressurizing medium lines are filledwith a gas, e.g. with air. The piston/cylinder assemblies thenadditionally serve as “pneumatic shock-absorbing legs”, this increasingthe riding comfort, in particular during off-road uphill or downhillriding.

[0016] In accordance with a further development of the invention, alocking device is provided for locking the piston/cylinder assembly ofthe rear wheel. Optionally, a corresponding locking device may also beprovided for the piston/cylinder assembly of the front wheel. Thelocking device may, for instance, be a double-acting hydraulic cylinderthat is integrated into the housing of the piston/cylinder assemblyintended for height adjustment, and that is e.g. filled with oil. Twochambers of the hydraulic cylinder are connected with one another via ahydraulic line and a shut-off device, wherein “hydraulic” locking ispossible by shutting off the shut-off device. As an alternative to adouble-acting hydraulic cylinder, a mechanical locking device may alsobe provided. The hydraulic cylinder also may have one chamber only whichis connected with a hydraulic reservoir via a check valve.

[0017] According to a further development of the invention, one shut-offdevice is provided in each of the two pressurizing medium lines thatconnect the piston/cylinder assemblies. Preferably, these tow shut-offdevices can be actuated by a common actuator. Furthermore, one singleactuator may be provided for the shut-off devices and the lockingdevice. Furthermore, both pressurizing medium lines may be connectedwith one another via a bypass line that can be shut off, so as tocompensate the pressure in both pressure circuits.

[0018] In accordance with a further development of the invention, aspring element is provided at the front-wheel suspension and/or at therear-wheel suspension. Springiness may be achieved by pneumaticpiston/cylinder assemblies and/or by separate or additional springelements. The spring means of the front-wheel and/or the rear-wheelsuspensions thus can be “decoupled” from adjusting devices. In the caseof “separately” provided spring means, the height adjustment could alsobe effected hydraulically. As spring elements, e.g. compression springsor elastomer elements may be used. The mechanical spring elements mayalso be integrated into the piston/cylinder assembly of the front-wheelor rear-wheel suspensions, respectively. A spring element may, forinstance, be incorporated into the plus chamber of the piston/cylinderassembly. In the case of strong shocks, where the “pneumatic” range ofspring is made full use of, an additional mechanical spring effect thuscan be achieved. Alternatively, an arrangement outside thepiston/cylinder assembly is also possible.

[0019] According to a further development of the invention, afilling/draining valve is provided for filling or draining,respectively, the piston/cylinder assemblies or the pressurizing mediumlines, respectively. The filling valve may be a check valve that openswith a predetermined pressure only, wherein the pressure can beadjustable. The “pneumatic spring strength” thus can be adjusted inaccordance with the weight of the cyclist and the desired ridingcomfort. Preferably, a compressed-air reservoir, e.g. a compressed-aircylinder, is provided, which may be integrated in the bicycle frame,which is very space-saving. Additionally, a compressed-air generator maybe provided, which is preferably arranged such that ambient air issucked in and pressed into the compressed-air reservoir or thepiston/cylinder assemblies, respectively, by springing in of the frontwheel or of the rear wheel, respectively. A compressed-air generatorfunctioning according to the principle of an air pump may, for instance,be used.

[0020] In accordance with a further development of the invention, thebicycle comprises a fork, wherein both fork arms each are formed by apiston/cylinder assembly. The rear wheel may be mounted on a swing armrear suspension that is connected with the frame via a lag hinge and thepiston/cylinder assembly for height adjustment of the rear wheel.

[0021] In a second basic variant of the invention, two cylinder chambersof the piston/cylinder assembly that are separated from each other by apiston, i.e. a “plus chamber” and a “minus chamber”, can be connectedwith one another via a fluid channel, this causing a pressurecompensation to be effected.

[0022] At one of the two sides of the piston, a piston rod is fastened,which stands out from the piston/cylinder assembly and can be shiftedaxially. Thus, the size of the effective piston area of the plus chamberdiffers from the effective piston area of the minus chamber, namely bythe cross-sectional area of the piston rod. Due to the differing sizesof the effective piston areas, a “difference force” on the piston or thepiston rod, respectively, results even when the pressure in the twocylinder chambers is equally high, which enables an automatic extendingof the adjusting devices.

[0023] In a third basic variant of the invention, effective piston areasof different sizes are also allocated to the two cylinder chambers, butthe cylinder chambers here are permanently separated from one another bythe piston. Furthermore, a locking device for locking the piston isalways provided in this basic variant. This variant thus is particularlysuited as adjusting device for a saddle or a steering stem,respectively, of a bicycle, where mechanical locking is absolutelynecessary.

[0024] The adjusting device according to the invention can be used formany purposes, e.g. for the height adjustment of the front-wheelsuspension, the rear-wheel suspension, the saddle or the steering stem.A substantial advantage consists in that the adjusting device isautomatically extendable by pressure energy that is stored in thepiston/cylinder assembly.

[0025] In the following, the invention will be explained in detail bymeans of embodiments in connection with the drawings, in which:

[0026]FIG. 1 shows a first embodiment of an adjusting device accordingto the invention;

[0027]FIG. 2 shows a second embodiment of an adjusting device accordingto the invention;

[0028]FIG. 3 shows an embodiment of an adjusting device with a hydrauliclocking device and a compensation reservoir;

[0029]FIG. 4 shows a further embodiment of an adjusting device with acompensation reservoir;

[0030]FIG. 5 shows an embodiment of an adjusting device with amechanical compensation means;

[0031]FIG. 6 is a schematic representation of a variant of theinvention;

[0032]FIG. 7 shows a bicycle in accordance with the invention;

[0033]FIG. 8 shows the piston/cylinder assemblies of the embodiment ofFIG. 7 in enlarged representation;

[0034]FIG. 9 shows a further embodiment in accordance with theinvention;

[0035]FIG. 10 shows a modification of the locking device;

[0036] FIGS. 11-15 show further embodiments in accordance with theinvention;

[0037]FIG. 16 shows an adjusting device for the height adjustment of asaddle; and

[0038]FIG. 17 shows a further adjusting device for the height adjustmentof a saddle.

[0039]FIG. 1 shows an adjusting device formed by a piston cylinderassembly 14, and a spring or damper element 20 “axially” connectedtherewith. The piston cylinder assembly 14 comprises a cylinder housing38 which incorporates a piston rod 19. The piston rod 19 comprises apneumatic piston 39 at its free end portion and a hydraulic piston 40spaced apart from the pneumatic piston 39. The pneumatic piston 39divides the cylinder housing 38 into a first pneumatic cylinder chamber41, which is referred to as “plus chamber”, and a second pneumaticcylinder chamber 42, which is referred to as “minus chamber”, with apassage opening 55 being provided in the pneumatic piston 39 to connectthe plus chamber 41 and the minus chamber 42 with one another.Consequently, the same pressure prevails in the plus chamber 41 and inthe minus chamber 42. The second pneumatic cylinder chamber 42 islimited by the pneumatic piston 39, the cylinder housing 38 and ahousing wall 38 a that comprises a piston opening which the piston rod19 passes through.

[0040] Furthermore, a filling junction 56 is provided that can be shutoff via a check valve 15 and that enables a filling of the plus chamber41 or of the minus chamber 42, respectively, connected therewith.Furthermore, a hinged bracket 57 is provided externally at the cylinderhousing 38, through which the adjusting device can be flexibly connectedwith some other component, e.g. the frame of a bicycle.

[0041] When comparing the plus chamber 41 and the minus chamber 42, itbecomes apparent that the plus chamber 41 has the shape of a circularcylinder and the minus chamber 42 the shape of an annular cylinder thatis limited by the inner side of the cylinder housing 38 and the pistonrod 19. In other words, the piston area of the plus chamber 41 is largerby the cross-sectional area of the piston rod 19 than the piston area ofthe minus chamber 42. When a pressure above atmospheric pressureprevails in the plus chamber 41 and in the minus chamber 42, a pistonforce results from the “cross-sectional area difference” of the pistonareas of the plus chamber 41 and the minus chamber 42 that is equal tothe product of the pressure prevailing in the plus chamber 41 or in theminus chamber 42, respectively, and the cross-sectional area of thepiston rod 19 (friction forces have not been taken into account here).Provided that the piston rod 19 is freely shiftable in the cylinderhousing 38, it thus is always pushed to an “extended” position due tothe resulting pressure force, i.e. to the “right” with respect to thecylinder housing 38.

[0042] The hydraulic piston 40 further divides the cylinder housing 38into a first hydraulic cylinder chamber 43 and a second hydrauliccylinder chamber 44, which are e.g. filled with oil. The two hydrauliccylinder chambers 43, 44 are connected with one another via a hydraulicline 45 that can be shut off by means of a check valve 46.

[0043] The piston rod 19 stands out from the cylinder housing 38 throughan opening in the housing in the section of the second hydrauliccylinder chamber 44 and comprises at its other free end portion a springpiston 47 which is incorporated in a housing 48 of the spring element20. The “adjusting device”, i.e. the piston/cylinder assembly 14, thusis “decoupled” from the spring means 20. In the interior of the housing48, a mechanical spring or an elastomer element may, for instance, bearranged. The housing 48 comprises a hinged bracket 58 for flexibleconnection with some other component, e.g. with the swing arm rearsuspension of a bicycle.

[0044] In the following, the functioning will be explained in detail.

[0045] When the check valve 46 is closed, the piston rod is “locked” dueto the incompressibility of the hydraulic fluid in the hydrauliccylinder chambers 43, 44, i.e. the hydraulic cylinder acts as a lockingdevice. The assembly shown thus only has an axial degree of freedomleft, namely the longitudinal elasticity of the spring element 20.

[0046] When the check valve 46 is opened, the piston rod 19 is freelyshiftable in the cylinder housing 38. Unless any “external forces” areexerted on the hinged brackets 57, 58, the piston rod automaticallyextends due to the resulting pressure force as explained above, theresulting pressure force being proportional to the pressure prevailingin the plus chamber 41 or the minus chamber 42, respectively. Byexerting axial pressure forces on the hinged brackets 57, 58, the pistonrod 19 may be pushed into the cylinder housing 38 and, by closing thecheck valve 46, may infinitely variably be “locked” hydraulically.

[0047] The adjusting device thus can be used universally, in particularwith a bicycle for the height adjustment of a wheel suspension, of thesaddle, the steering stem etc., which will be explained in detail still.

[0048]FIG. 2 shows a variant of the embodiment of FIG. 1, where the pluschamber 41 and the minus chamber 42 are connected with one another viaan “external” pneumatic line 59 and a check valve 60. When the checkvalve 46 of the hydraulic line 45 is opened and the check valve 60 isclosed, a balance of powers occurs at the pneumatic piston 19, whereinthe pneumatic piston 39 assumes a neutral position between its two endpositions. When the check valve 60 is additionally opened, so that apressure compensation between the plus chamber 41 and the minus chamber42 can take place, the pneumatic piston extends completely, i.e. itassumes its “right” end position. The check valve 60 or the pneumaticline 59, respectively, may further comprise a filling junction (notillustrated) for filling the plus chamber 41 or the minus chamber 42,respectively.

[0049]FIG. 3 shows an embodiment in which also a piston/cylinderassembly 14 and a spring element 20 are provided. The cylinder housing38 and the housing 48 of the spring element in this case are integrallyconnected with one another. As an alternative, a coupling joint (notillustrated) may also be provided. Such a variant with a coupling jointwill be explained in connection with FIG. 11.

[0050] The cylinder housing 38 incorporates a piston 61 of a pistonelement 62. The piston element 62 or the piston 61, respectively, dividethe cylinder housing 38 into an annular plus chamber 41 and an annularminus chamber 42 which, in analogy with the embodiments of FIGS. 1 and2, is allocated a smaller area of the piston 61 than the plus chamber41. In analogy with FIG. 1, the piston 61 comprises a passage opening 55that connects the plus chamber 41 and the minus chamber 42 with oneanother. Furthermore, a filling junction 56 as well as an allocatedcheck valve 15 are provided here, too.

[0051] The cylinder housing 38 in this case comprises a piston-shapedelement 63 which is incorporated in the piston element 62 and iscomponent of a hydraulic piston/cylinder assembly with a first hydrauliccylinder chamber 43 and a second hydraulic cylinder chamber 44. Inanalogy with FIGS. 1 and 2, respectively, the two hydraulic cylinderchambers 43, 44 are connected with one another via a hydraulic line anda check valve, which is not illustrated here. The hydraulic line and thecheck valve may, for instance, be arranged in a plane perpendicular tothe drawing plane.

[0052] The second hydraulic cylinder chamber 44 further is, via ahydraulic line 64 provided in the cylinder housing 38 and a hydrauliccheck valve 65, in connection with a compensation reservoir that isillustrated only schematically as housing 66 with a float 67. Thecompensation reservoir 66 is necessary since differently sized pistonareas of the piston-shaped end portion 63 are allocated to the hydrauliccylinder chambers 43, 44, i.e. when the piston element 62 is shifted, agreater volume has to flow off the one hydraulic cylinder chamber thanflows into the other hydraulic cylinder chamber. The “difference volume”then flows into the compensation reservoir 66 or from the compensationreservoir 66 into one of the two hydraulic cylinder chambers,respectively. By shutting off the check valve 65, the piston element 62may be “locked”, with a “volume compensation” via the compensationreservoir 66 being prevented. When, however, the check valve 65 is open,an unhindered “length adjustment”, i.e. a shifting of the piston element62 in the cylinder housing 38, is possible, with the piston element 62extending “automatically” in this case, too, when the pressureprevailing in the cylinder chambers 41, 42 is higher than theatmospheric pressure and no or only minor external pressure forces areapplied.

[0053] As an alternative to the embodiment described above, the twocylinder chambers 43, 44 need not necessarily be connectable with oneanother via a hydraulic line. The cylinder chamber 43 my also be filledwith a gas or with air, respectively, which results in excess pressureor negative pressure, respectively, occurring when the piston element 62is shifted in the cylinder chamber 43. Alternatively, the cylinderchamber 43 may also be open towards the atmosphere, so that anunhindered exchange of air is possible. In the two latter-mentionedvariants, it is not a “difference volume”, but the entire hydraulicfluid volume that flows into the compensation reservoir 66 or from thecompensation reservoir 66 to the cylinder chamber 44, respectively, whenthe piston element 62 is shifted. The two latter-mentioned variantsfurther have the advantage that the effective area of the piston-shapedend portion 63 is larger than in the variant described above. In otherwords, the piston area generating the hydraulic pressure is larger andthus bears higher forces in the case of minor pressure.

[0054] In analogy with FIGS. 1 and 2, hinged brackets 57, 58 areprovided here, too, through which the adjusting device is flexiblyconnectable with other components of a bicycle.

[0055]FIG. 4 shows a variant of the embodiment of FIG. 3, where the pluschamber 41 and the minus chamber 42 are connected with one another viaan “external” pneumatic line 59 and a check valve 60.

[0056] Of course, a “filling line” (not illustrated) may also beprovided here for filling the plus chamber 41 or the minus chamber 42,respectively, with a gas or with air.

[0057]FIG. 5 shows an embodiment in which a compensation means 87 formedby an annular piston 88 and a spring 89, which are shiftable in thepiston element 62, is provided for the “volume compensation” between thefirst hydraulic cylinder chamber 43 and the second hydraulic cylinderchamber 44. The pressure prevailing in the cylinder chamber 43 pressesonto the annular piston 88 contrary to the pressure force of the spring89 which is supported against a wall 90 of the piston element 62. Thespring force and the pressure prevailing in the cylinder chamber 43 thusare at equilibrium. The cylinder chamber 43 further is in connectionwith the check valve 65 via a hydraulic line 91. From the check valve65, another hydraulic line 92 leads to the cylinder chamber 44. Here,too, the piston-shaped end portion 63 seals the cylinder chamber 43against the cylinder chamber 44.

[0058] When the check valve 65 is open, the piston element 62 thus canbe shifted in the cylinder housing 38. Due to the differentcross-sectional areas of the cylinder chambers 43, 44, a volumecompensation is necessary, which is effected in this case by shifting ofthe annular piston 88. Alternatively to the mechanical spring 89 asillustrated, a pneumatic spring or another mechanical spring,respectively, may also be provided.

[0059]FIG. 6 is a schematic illustration showing that the pneumaticpiston 39 and the hydraulic piston 40 may, alternatively to theembodiments described above, also be arranged “in parallel” and may beconnected with one another and with the spring element 20 via axiallyshiftable rods 68. Furthermore, the hydraulic check valve 46, via whichthe hydraulic cylinder chambers 43, 44 are connectable with each other,and the hydraulic check valve 65, via which the hydraulic cylinderchamber 43 is connectable with the compensation reservoir 66, may beincluded in one common unit 69, e.g. in a common housing.

[0060] In the following Figures, the invention will be explainedspecifically in connection with a bicycle.

[0061]FIG. 7 illustrates a bicycle having a frame 1 that comprises alongitudinal rod 2, a saddle rod 3 and a connecting rod 4. At the commonend portion of the longitudinal rod 2 and the connecting rod 4, asteering head bearing 5 is provided, in which one end portion of a frontfork 6 or a steering stem 7 that is connected therewith, respectively,is rotatably mounted, on which a handle bar 8 is mounted. The front fork6 comprises two fork arms, one of which is illustrated only, which isformed by a piston/cylinder assembly 9 that will be explained in detailin connection with FIG. 8. As an alternative to the embodimentillustrated here, a fork having only one fork arm may also be provided.At the free end portion 10 of the piston/cylinder assembly 9, a frontwheel 11 is rotatably mounted.

[0062] From the piston/cylinder assembly 9, a first pressurizing mediumline 12 and a second pressurizing medium line 13 lead to a secondpiston/cylinder assembly 14, wherein a first check valve 15 is providedin the first pressurizing medium line 12 and a second check valve 16 isprovided in the second pressurizing medium line 13.

[0063] A housing end portion 17 of the second piston/cylinder assembly14 is connected with the connecting rod 4 via a lag hinge 18.

[0064] A piston rod 19 of the second piston/cylinder assembly 14 isconnected with a spring element 20 which will also be explained indetail in connection with FIG. 8. One end portion 21 of the springelement 20 is connected via a lag hinge 22 with a swing arm rearsuspension 23 which here consists of three communicating rods 24, 25 and26, and which is provided for the rotatable mounting of a rear wheel 27.The swing arm rear suspension 23 is connected via a lag hinge 28 withthe saddle rod 3, at the free end portion of which a saddle 3 a ispositioned. The lag hinge 28 here is arranged above a pedal bearing 29.Alternatively, the lag hinge 28 may also be arranged such that itsswiveling axis coincides with the rotational axis of the pedal bearing29.

[0065]FIG. 8 illustrates an enlarged section of the bicycle of FIG. 7.

[0066] The piston/cylinder assembly 9 consists of a pneumatic cylinder30 which incorporates a piston 31. The piston 31 comprises a piston rod32 with a piston rod interior 33. The piston 31 divides the pneumaticcylinder 30 into a first cylinder chamber 34, which may be referred toas “plus chamber”, and a second cylinder chamber 35 that is annular andthat is limited by the pneumatic cylinder 30 and the piston rod 32. Thepiston 31 further comprises a connecting channel 36 that connects thepiston rod interior 33 with the second cylinder chamber 35 and may beformed as a nozzle or throttle point so as to effect damping duringspringing. The piston rod interior 33 and the second cylinder chamber 35together form a “minus chamber” of the piston/cylinder assembly. The“plus chamber” 34 has a piston area that is larger by thecross-sectional area of the piston rod 32 than that of the “minuschamber” formed by the piston rod interior 33 and the second cylinderchamber 35.

[0067] The minus chamber serves as a progressively adjustablecounter-spring.

[0068] The connecting channel 36 has a relatively small cross-sectionand acts as “throttle” or “damping element” during springing in orspringing out, respectively. The cross-section, however, need notnecessarily be small and constitute a throttle point.

[0069] The end portion of the piston rod 32 that is opposite the piston31 is connected with a conducting tube 37 that is provided forconducting the pneumatic cylinder 30. The pneumatic cylinder 30 and theconducting tube 37 thus constitute a telescopic shock-absorbing legwhich here is a fork arm of the front fork. At the free end portion 10of the conducting tube 37 the front wheel 11 is mounted.

[0070] The first pressurizing medium line 12 is connected with the firstcylinder chamber 34, and the second pressurizing medium line 13 isconnected with the piston rod interior 33. The piston rod interior 33may also be considered as “elongated pressurizing medium line 13”. Viathe check valves 15, 16, the pressurizing medium lines 12, 13 areconnected with the second piston/cylinder assembly 14.

[0071] Furthermore, the pressurizing medium lines 12 and 13 can beconnected with one another via a bypass line 12 into which a check valve15′ has been incorporated, so as to adjust the same pressure in bothpressure circuits. Thus, only one valve 12″ that is connected to one ofthe lines 12, 12′ or 13 at any place, is required for building uppressure, i.e. for “pumping up”.

[0072] The “actuators” or valves 15, 15′, respectively, may be arrangedsuch that they can easily be reached by the cyclist even during riding,e.g. in the region of the steering head bearing 5 or the handle bar 8,respectively.

[0073] The second piston/cylinder assembly 14 comprises a cylinderhousing 38 which incorporates the piston rod 19. The piston rod 19comprises a pneumatic piston 39 and a hydraulic piston 40. The pneumaticpiston 39 divides the cylinder housing 38 into a first pneumaticcylinder chamber 41, which is referred to as “plus chamber”, and asecond pneumatic cylinder chamber 42, which is referred to as “minuschamber”. Here, too, the “plus chamber” 41 has a piston area that isgreater by the cross-sectional area of the piston rod 19 than that ofthe “minus chamber” 42. Since both “plus chambers” 34, 41 have a largerpiston area than the allocated minus chambers, a sufficiently strong“pneumatic spring” can be obtained, with the spring strength dependingon the pressure in the chambers.

[0074] The second pneumatic cylinder chamber 42 is limited by thepneumatic piston 39, the cylinder housing 38, and by a housing wall 38 athat comprises a piston opening through which the piston rod 19 isconducted. The first pneumatic cylinder chamber 41 is connected with thefirst pressurizing medium line 12 and the second pneumatic cylinderchamber 42 is connected with the second pressurizing medium line 13.

[0075] The hydraulic piston 40 divides the housing 38 further into afirst hydraulic cylinder chamber 43 and a second hydraulic cylinderchamber 44, which are e.g. filled with oil. The two hydraulic cylinderchambers 43, 44 are connected with one another via a hydraulic line 45that can be shut off by means of a check valve 46.

[0076] At the end portion of the piston rod 19 opposite to the pneumaticpiston 39 a spring piston 47 is provided which is incorporated in ahousing 48 of a spring element 20. The “adjusting device”, i.e. thepiston/cylinder assembly 14 of the rear wheel 27, thus is completelydecoupled from the spring element 20. Such decoupling would also bepossible at the front fork. In the interior of the housing 48 amechanical spring or an elastomer element may, for instance, bearranged. The housing 48 is connected with the swing arm rear suspension23 via the end portion 21 and the lag hinge 22.

[0077] In the following, the functioning will be explained in detail.

[0078] When the check valve 46 is closed, the piston rod 19 is locked bythe hydraulic fluid in the hydraulic cylinder chambers 43, 44. Via thespring element 20 the swing arm rear suspension 23 is “springily”, i.e.pivotable about the lag hinge 28, connected with the frame 1.

[0079] The piston rod 32 forms a “pneumatic spring” with the pneumaticcylinder 30 and the gas volume included in the first cylinder chamber 34and in the first pressurizing medium line 12, wherein the first cylinderchamber 34 is in connection with the first pneumatic cylinder chamber 41when the check valve 15 is open. During “springing in” of the piston rod32 the pressure in the first cylinder chamber 34 or in the firstpressurizing medium line 12 and in the first pneumatic cylinder chamber41, respectively, increases. Accordingly, the pressure decreases in thesecond pressurizing medium line 13, the piston rod interior 33 and thesecond cylinder chamber 35.

[0080] When the check valves 15, 16 and 46 are open, the piston rod 19can be shifted in the direction of the saddle rod 3, with hydraulicfluid flowing from the hydraulic cylinder chamber 44 via the hydraulicline 45 into the first hydraulic cylinder chamber 43. By shifting thepiston rod 19, the swing arm rear suspension 23 rotates clock-wisearound the lag hinge 28 whereby the rear wheel is “lowered”. With theshifting of the piston rod 19, the pneumatic piston 39 is also shifted,which results in that air flows from the second pneumatic cylinderchamber 42 via the second pressurizing medium line 13 into the pistonrod interior 33 or the second cylinder chamber 35, respectively. Thiscauses the piston 31 to be pressed upwards, which results in air flowingover from the first cylinder chamber 34 into the first pneumaticcylinder chamber 41. By the shifting of the piston 31 or the piston rod32, respectively, the pneumatic cylinder 31 is pushed into theconducting tube 37, whereby the length of the front fork is reduced andthe rear wheel is “extended”. This fork or rear wheel adjustment isespecially suited for riding uphill.

[0081] Vice versa, by pressing down the saddle rod 31, the piston rod 19can be shifted in the direction of the connecting rod 4, whereby theswing arm rear suspension is swiveled counter-clockwise and the lengthof the front fork is extended.

[0082] After adjusting a desired front wheel height or rear wheelheight, respectively, the check valves 15, 16, 46 are closed. By“retracting” of the front fork 31 and “extending” of the rear wheel, thesitting position can be adjusted such that the cyclist is seated almosthorizontally during uphill riding. Accordingly, a “downhill ridingposition” can be adjusted by extending the front fork and retracting therear wheel.

[0083] As an alternative to the illustrated “locking device” formed bythe hydraulic cylinder chambers 43, 44 and the check valve 46, a“mechanical fixing device” for fixing the piston 19 may also beprovided. Furthermore, the cylinder chambers 34, 35, 41 and 42 as wellas the pressurizing medium lines 12, 13 may also be filled with ahydraulic fluid. Due to the incompressibility of the hydraulic fluid,the piston/cylinder assembly 9 then is, however, rigid when the checkvalves 15, 16 are closed. In this variant, a mechanical suspension thatis “decoupled” from the piston/cylinder assembly 9 may, however, beprovided, for instance by a spring element that springily connects thefront fork with the steering head bearing 5.

[0084] The two check valves 15 and 16 and the check valve 15′ in thebypass line 12′ may further be designed and arranged such that they canbe actuated by a common actuator (not illustrated). Furthermore, thepressurizing medium lines 12, 13 can be incorporated in the interior ofthe frame 1, i.e. in the interior of the connecting rod 4.

[0085] In the embodiment shown in FIG. 8, the pneumatic cylinderchambers 34, 35 of the piston/cylinder assembly 9 at the front fork andthe pneumatic cylinder chambers 41, 42 can be connectable with oneanother via a respective pressurizing medium line in which a shut-offdevice is arranged. By means of the shut-off device, a separate, i.e.independent, adjustment of the piston/cylinder assembly 9 and of thepiston/cylinder assembly 14 is possible. By means of the shut-offdevice, the cylinders may be maintained on different levels. Thisvariant is of particular advantage when only one adjustable fork or onlyone adjustable rear assembly damper is provided.

[0086] As an alternative to the embodiment of FIG. 8, the locking devicemay also comprise a single-acting cylinder. This single-acting cylindermay e.g. be integrated in a common cylinder housing of thepiston/cylinder assembly 14 of the rear wheel suspension. Thesingle-acting cylinder may furthermore be connected with a compensationreservoir via a pressurizing medium line in which a shut-off device isprovided. By means of the shut-off device, the single-acting cylindermay be separated from the compensation reservoir. The locking devicethus can also be put into practice by means of a single-acting cylinder,a compensation reservoir and a shut-off device.

[0087] Furthermore, the pressurizing medium lines 12, 13 can beconnected with one another via a further pressurizing medium line and afurther shut-off device. This makes it possible to open the entiresystem, which enables a simple adjustment of the individual chambers ofthe piston/cylinder assemblies.

[0088]FIG. 9 shows a variant of the embodiment of FIGS. 7 and 8.

[0089] In the embodiment of FIG. 9, the pneumatic cylinder 30 is longerthan with the embodiment of FIGS. 6 and 7, this resulting in a longerrange of spring. In the pneumatic cylinder 30, an element 49 ofresilient material and, further, a “floater element” 50 are arrangedabove the pneumatic piston 31; the “floater element” 50 seals the firstcylinder chamber 34 against the cylinder chamber in which the resilientelement 49 is arranged. Furthermore, clampings may be provided thatwould clamp the piston, with the “length” being extendable downwards.

[0090] The resilient element 49 improves the springing properties andserves as suspension in the so-called “uphill position”, i.e. duringuphill riding. During uphill riding, the piston/cylinder assembly 9 isretracted, i.e. the first cylinder chamber 34 has a smaller volume thanin FIG. 9 or the volume zero, respectively, with the floater elementthen abutting at the handle bar-side end portion of the pneumaticcylinder 30. In this position, the “range of pneumatic spring” isrelatively small or zero, respectively. By means of the resilientelement 49, a certain “residual suspension” may be maintained, though.

[0091] The “additional elastomer chamber” thus primarily serves asemergency suspension, in particular for the case that thepiston/cylinder assembly 9 leaks and air escapes. The cyclist thus willalways arrive safely at home even in the case of a defect. This“elastomer chamber” always springs synchronously to the plus chamber 34.In the uphill position, the plus chamber 34 is “almost” zero. Thus, theplus chambers of fork and rear assembly and the minus chambers are onlyalmost identical. Tests have shown that some air still remains in thefork, i.e. in the piston/cylinder assembly 9, even when the rearassembly has been completely extended.

[0092] Alternatively or in supplement to the resilient element 49, amechanical spring element, such as a coil spring or a pre-filledcompressed-air cylinder which simply is inserted, may also be used. Thecoil spring may, in accordance with FIG. 9, be positioned between thepiston 31 and the floater element 50, or between the floater element 50and the handle bar-side end portion of the pneumatic cylinder 30.

[0093] Alternatively to the resilient element 49, an additionalpneumatic spring element may also be provided.

[0094]FIG. 10 shows a modification of the locking device, wherein onlythe cylinder chamber 43 is, via the check valve 46, connected with ahydraulic reservoir 44′ that serves as compensation reservoir when thepiston rod 19 is shifted. When the check valve 46 is closed, the pistonrod 19 is definitely fixed due to the incompressibility of the hydraulicfluid in this device, too.

[0095] Alternatively to the piston/cylinder assembly 14 described inFIGS. 6, 7 or 9, other ones of the above-mentioned embodiments may alsobe used.

[0096] It is in particular also possible to provide an adjusting deviceexclusively at the front wheel suspension or at the rear wheelsuspension, respectively, or to provide completely separate adjustingdevices for the front wheel suspension and the rear wheel suspension,which are neither pneumatically nor hydraulically coupled with oneanother.

[0097]FIG. 11 shows a variant of the embodiment of FIG. 5, with thecylinder housing 38 and the spring element 20 being flexibly connectedvia a lag hinge 93. The cylinder housing 38 is mounted via the hingedbracket 57 on a supporting element 94 of the connecting rod 4, and thehinged bracket 58 of the spring element 20 is flexibly mounted on theswing arm rear suspension 23. By means of such a “non-lineararrangement” of adjusting unit and spring element, the “angle of attack”of the spring element 20 may, moreover, be changed progressively ordecreasingly, respectively.

[0098] The adjusting unit, i.e. the cylinder housing 38, mayadditionally be conducted along the connecting rod 4, e.g. by a bar orthe like.

[0099]FIG. 12 shows a schematic embodiment with two adjusting devices,namely a piston/cylinder assembly 9, and a further adjusting device 70that corresponds substantially to that of the embodiment of FIG. 6. Thepiston/cylinder assembly 9 may, for instance, be provided for adjustingthe front wheel suspension, and the adjusting device 70 for adjustingthe rear wheel suspension (cf. FIG. 7). The first cylinder chamber 34,i.e. the plus chamber of the piston/cylinder assembly 9, is connectedwith the plus chamber 41 of the adjusting device 70 via the firstpressurizing medium line 12 and the shut-off device 15. Furthermore, thesecond cylinder chamber 35, i.e. the minus chamber of thepiston/cylinder assembly 9, is connected with the minus chamber 42 ofthe adjusting device 70 via the pressurizing medium line 13 and theshut-off device 16.

[0100] In the embodiment of FIG. 12, two resilient elements 49 a, 49 bare arranged between the pneumatic piston 31 and the floater element 50,in contrast to FIG. 9. The resilient elements 49 a, 49 b improve thesuspension properties and serve as suspension in the so-called “uphillposition”, i.e. during uphill riding. During uphill riding, thepiston/cylinder assembly 9 is retracted, i.e. the first cylinder chamber34 has a relatively small volume, or the volume zero, respectively, withthe floater element then abutting at the handle bar-side or upper endportion of the pneumatic cylinder 30. In this position, the “range ofpneumatic spring” is relatively small or zero, respectively. Theresilient elements 49 a, 49 b then ensure a certain “residual springeffect”. The resilient elements 49 a, 49 b in particular may bemanufactured of different materials, i.e. they may have different springstrengths.

[0101] An annular resilient element 71 is arranged at the piston rod 32and serves as return element in the so-called “downhill position” inwhich the piston/cylinder assembly 9 is extended. The resilient element71 prevents the piston 31 from hitting against the lower end portion ofthe pneumatic cylinder during springing out.

[0102]FIG. 13 shows a further embodiment with two adjusting devices thatare coupled with one another. The first adjusting device is formed bythe piston/cylinder assembly 9 and concurs with that of the embodimentof FIG. 12. The second adjusting device 70 comprises a cylinder housing38 in which the piston element 62 is shiftably incorporated. The piston61 of the piston element 62 slides in a recess 71 of the cylinderhousing 38 and divides the recess 71 into the first hydraulic cylinderchamber 43 and the second hydraulic cylinder chamber 44, which can beconnected with one another via the hydraulic line 45 or the check valve46, respectively.

[0103] The piston element 62 further comprises an inner recess 72 inwhich the pneumatic piston 39 slides. The pneumatic piston 39 here is anintegral component of the cylinder housing 38 and divides the recess 72into the first pneumatic cylinder chamber 41 or “plus chamber” and thesecond pneumatic cylinder chamber 42 or “minus chamber”.

[0104] The piston element 62 is further slidably conducted at a pistonrod-like element 73 and at a further cylinder-shaped recess 74 of thecylinder housing 38. At each axial end portion of the recesses 72 and74, resilient elements 75 or 76, respectively, are arranged, whichprevent the piston element 62 from hitting against the cylinder housing38.

[0105] The plus chamber 41 is connected with the first cylinder chamber34, i.e. with the plus chamber of the piston/cylinder assembly 9, via apneumatic line 75 and a resilient pneumatic pressurizing medium line 12as well as the check valve 15. The second pneumatic cylinder chamber 42,i.e. the minus chamber, is connected with the minus chamber of thepiston/cylinder assembly 9 via the pressurizing medium line 13 and thecheck valve 16. At one end portion of the adjusting device 70, a springelement 20 or a damping element, respectively, is provided like with theembodiments of FIGS. 1 to 7 and 9.

[0106] In this embodiment, too, the piston area allocated to the pluschamber 41 is larger than the piston area allocated to the minus chamber42. Consequently, here, too, an axial force results that automaticallyextends the piston element 62 when the check valve 46 is open and whenthe “plus circuit” is connected via the line 12 with the “minus circuit”via the line 13. A hydraulic compensation reservoir is not necessary inthis embodiment since the annular areas of the hydraulic cylinderchambers 43, 44 have the same annular cross-sections, i.e. the volumeflowing off the one hydraulic cylinder chamber flows into the otherhydraulic cylinder chamber and vice versa. FIG. 14 shows an embodimentof the piston/cylinder assembly 9 in which the plus chamber 34 can bedirectly connected with one another via the pressurizing medium line 12and the check valve 15. When the check valve 15 is opened, a pressurecompensation occurs between the plus chamber 34 and the minus chamber35. Unless any external axial forces are exerted on the piston/cylinderassembly 9, the pneumatic cylinder 30 is “automatically” pressed out ofthe conducting tube 37. Here, too, the cross-sectional area of thefloater element 50, which is impacted by the pressure prevailing in theplus chamber 34, is larger than the cross-sectional area of the piston31, which is impacted by the pressure of the minus chamber 35, with thedifference in the cross-sectional areas corresponding to thecross-sectional area of the piston rod 32. Since the same pressureprevails in the plus chamber 34 and the minus chamber 35 after the checkvalve 15 has been opened, a difference force results which effects theextending of the piston/cylinder assembly 9.

[0107]FIG. 15 shows a variant of the embodiment of FIG. 8. Theconducting tube 37 or the piston rod 32 connected therewith,respectively, here are positioned “at the top”, i.e. toward the steeringstem. At the “lower” free end portion of the piston rod 32 the piston 31is positioned, which is slidably incorporated in the pneumatic cylinder30. The pneumatic cylinder 30 is inserted longitudinally shiftably inthe conducting tube 37.

[0108] The first cylinder chamber 34, i.e. the “plus chamber”, is formedby the pneumatic cylinder 34 and the piston 31. The second cylinderchamber 35, i.e. the “minus chamber”, is an annular cylinder chamberthat is formed by the pneumatic cylinder 30, the piston rod 32 and thepiston 31. In the piston 31, a passage opening 55 is provided whichconnects the plus chamber 34 and the minus chamber 35 and which can beopened or closed, respectively, by means of a valve 84. The valve 84comprises an actuating device 85 that is conducted upwards through thepiston 31 or the piston rod 32, respectively, up to the height of thesteering stem 7. At the height of the steering stem 7, an actuator 86 isprovided which here has the shape of a switch or a draw-button,respectively. The actuating device 85 may, for instance, be a Bowdenwire. The valve 84 may, of course, also be actuated differently, forinstance electrically, hydraulically, pneumatically etc.

[0109] In the case of this embodiment, a height adjustment of the frontfork thus can in a particularly comfortable way be carried out from thehandle bar or steering stem 7, respectively. Of course, additionalspring elements may be incorporated in the plus chamber 34 here, too.

[0110]FIG. 16 shows an embodiment in which the adjusting device is usedfor the height adjustment of the saddle 3 a. The saddle 3 a comprises asaddle tube 75 that is inserted into the saddle rod 3 of the bicycleframe. Furthermore, a piston rod 76 is provided, which is connected withthe saddle rod 3 and projects upwardly therefrom. At the upper free endportion of the piston rod 76, a piston 77 is provided which slides inthe saddle tube 75. Furthermore, at the lower free end portion of thesaddle tube 75, a piston 78 is provided which has a recess through whichthe piston rod 76 extends. The saddle rod 3, the piston rod 76 and thepiston 78 form a plus chamber 79 that can be filled with a gas or withair, respectively, through a filling device (not illustrated). Thepistons 77, 78, the piston rod 76 and the saddle tube 75 form an annularminus chamber 80. Corresponding to the embodiment of FIG. 1, the pluschamber 79 and the minus chamber 80 may be in pressure connection via apassage opening (not illustrated) in the piston 78. If a pressureprevails in the plus chamber 79 which is higher than atmosphericpressure, an axial force results that acts in the direction of thesaddle 3 a. Furthermore, a hydraulic cylinder chamber 81 is providedwhich is limited by the saddle 3 a, the saddle tube 75 and the piston77. The hydraulic cylinder chamber 81 is in pressure connection with acompensation reservoir 66 via a hydraulic line 82 and via a check valve46. When the check valve 46 is opened, the saddle tube 75 is pushedupwards, whereby the volume of the hydraulic cylinder chamber 81 isincreased and hydraulic fluid flows in from the compensation reservoir66. By closing the shut-off device 46, the current height of the saddleis “locked”.

[0111] Furthermore, a “twisting security” may be provided for the saddlerod. The saddle tube and the saddle rod may, for instance, have an ovalcross-section, an externally arranged conducting rod may be provided, aconducting groove, an edge profile etc.

[0112]FIG. 17 shows a variant of the embodiment of FIG. 16. Here, thehydraulic cylinder chamber 81 provided in the saddle tube 75 is inconnection with the compensation reservoir 66 via a hydraulic line 83provided in the piston rod 76 and via the check valve 46. Thefunctioning on the opening of the check valve 46 corresponds to that ofthe embodiment of FIG. 16.

[0113]FIG. 18 illustrates an adjusting device for the height adjustmentof the front wheel suspension of a bicycle in accordance with a furtherembodiment of the present invention. A pneumatic cylinder 30 a is at itslower end portion mounted via a screw connection (or alternatively e.g.via a plug connection) on a conducting tube 37 a. A tube 37 b and apiston rod 32 a connected therewith is mounted on the steering stem 7 a.At the lower end portion of the piston rod 32 a, a piston 31 a isarranged, which is slidably conducted in the pneumatic cylinder 30 a.The tube 37 b and the piston rod 32 a are shiftable in longitudinaldirection vis-à-vis the conducting tube 37 a and the pneumatic cylinder30 a.

[0114] The first cylinder chamber 34 a, i.e. the “plus chamber”, isformed by the pneumatic cylinder 30 a. The second cylinder chamber 35 a,i.e. the “minus chamber”, is an annular cylinder chamber that is formedby the pneumatic cylinder 30 a, the piston rod 32 a and the piston 31 a.In the piston, a passage opening is provided which connects the firstcylinder chamber 34 a with the second cylinder chamber 35 a, and whichcan be opened or closed by a valve. The valve is connected with anactuating device 85 a that is conducted upwards through the piston 31 aor the piston rod 32 a, respectively, up to the height of the steeringstem 7 a. The actuating device 85 a comprises an actuator 86 a at theheight of the steering stem. When this is operated, the valve opens orcloses, respectively.

[0115] At the lower end portion of the pneumatic cylinder 30 a, anelement 33 a of a resilient material is positioned. A floater element 38a that seals the first cylinder chamber 34 a against the cylinderchamber in which the resilient element 33 a is arranged, is positionedthereabove. The floater element may alternatively be designed e.g.air-permeably. Embodiments without a floater element are alsoconceivable.

[0116] In an alternative embodiment that is not illustrated, twoadditional pressurizing medium lines are provided in an adjusting devicecorresponding to that illustrated in FIG. 18, which are conducteddownwards from the height of the steering stem 7 a through the pistonrod 32 a to the piston 31 a. The first pressurizing medium line is inconnection with the plus chamber 34 a, and the second pressurizingmedium line is in connection with the minus chamber 35 a. From theadjusting device illustrated in FIG. 18, the pressurizing medium lineslead to a second piston/cylinder assembly which may, for instance, bedesigned in accordance with the second piston/cylinder assembly 14 asillustrated in FIGS. 7 and 8. The first pressurizing medium line isconnected with the plus chamber 41, and the second pressurizing mediumline with the minus chamber 42 of the second piston/cylinder assembly14.

[0117]FIG. 19 illustrates an adjusting device formed by a pistoncylinder arrangement 14 a in accordance with a further embodiment of theinvention, which is especially suited for the height adjustment of therear wheel suspension. The piston cylinder arrangement 14 a comprises acylinder housing 38 a in which a piston rod 19 a with a pneumatic piston39 a is conducted. The pneumatic piston 39 a divides the cylinderhousing 38 a into a plus chamber 41 a and a minus chamber 42 a. The pluschamber 41 a is connected via a first opening 41 b, and the minuschamber 42 a via a second opening 42 b, with an “external” pneumaticline 59 a that can be opened and closed by a check valve 60 a. Theopenings 41 b, 42 b are provided in the middle wall of the cylinderhousing 38 a at a certain minimum distance from the right and leftcylinder end portions, e.g. more than 2 or 4 cm, respectively.

[0118] When the check valve 60 a is closed, an equilibrium of forcesoccurs at the pneumatic piston 19 a, with the pneumatic piston 19 aassuming the first neutral position illustrated in FIG. 19. Foradjusting the adjusting device, the check valve 60 a is opened.Consequently, the plus chamber 41 a and the minus chamber 42 a areconnected with one another, so that a pressure compensation between thechambers may take place. The pneumatic piston 19 a moves to the left.When it covers the second opening 42 b, the plus chamber 41 a and theminus chamber 42 a are separated again. An equilibrium of forces againoccurs at the pneumatic piston 19 a, with the pneumatic piston 19 aassuming a second neutral position. In this position, it is spaced apartfrom the left side wall of the cylinder housing 38 a. The path ofmovement thus is limited towards the left; a minimum range of springremains—even when the check valve 60 a is open. Then, the check valve 60a is closed.

[0119] For a new adjustment of the adjusting device, the check valve 60a is opened again, and the pneumatic piston 19 a is pressed to theright. In the course of the movement to the right, air flows from theplus chamber 41 a into the minus chamber 42 a. When the pneumatic piston19 a covers the first opening 41 b, the plus chamber 41 a and the minuschamber 42 a are separated again. The piston 19 a then can no longer (oronly with great effort) be pushed further to the right—the path ofmovement thus is also limited towards the right. When the check valve 60a is closed, an equilibrium of forces again occurs at the piston 19 a,with the piston 19 a assuming a third neutral position.

1. A bicycle comprising a frame and adjusting devices for adjusting theheight of the front wheel and rear wheel suspensions, characterized inthat said adjusting devices each comprise at least one double-actingpiston/cylinder assembly (9, 14) with a first cylinder chamber (34, 41)and a second cylinder chamber (33, 35 42) each, that said two first andsaid two second cylinder chambers (34, 41, 33, 35 42) each are connectedwith one another via an allocated pressurizing medium line (12, 13), andthat a shut-off device (15, 16) is provided in at least one of said twopressurizing medium lines (12, 13).
 2. The bicycle according to claim 1,characterized in that said two piston/cylinder assemblies (9, 14) andsaid pressurizing medium lines (12, 13) are filled with a gas.
 3. Thebicycle according to one of claims, 1 or 2, characterized in that alocking device (40, 43-46) is provided for locking said piston/cylinderassembly of said rear wheel suspension.
 4. The bicycle according toclaim 3, characterized in that said locking device (40, 43-46) is adouble-acting piston/cylinder assembly, the cylinder chambers (43, 44)of which can be connected with one another via a pressurizing mediumline (45) and a shut-off device (46) positioned in said pressurizingmedium line (45).
 5. The bicycle according to claim 4, characterized inthat said cylinder chambers (43, 44) are filled with a gas or air,respectively.
 6. The bicycle according to claim 4, characterized in thatsaid locking device (40, 43-46) is a double-acting hydraulic cylinder,wherein said two cylinder chambers (43, 44) are separated from eachother by a hydraulic piston (40) which is connected with saidpiston/cylinder assembly (14) of said rear wheel suspension, and thatsaid hydraulic chambers (43, 44) of said hydraulic cylinder can beconnected with one another via a hydraulic line (45) and a shut-offdevice (46) positioned in said hydraulic line (45).
 7. The bicycleaccording to claim 3, characterized in that said locking device is asingle-acting piston/cylinder assembly, the cylinder chamber (43) ofwhich is connected with a compensation reservoir (44′) via apressurizing medium line and a shut-off device (46).
 8. The bicycleaccording to one of claims 3 to 7, characterized in that saidpiston/cylinder assembly (14) of said rear wheel suspension and saidlocking device (40, 43-46) of said rear wheel suspension have a commoncylinder housing (38).
 9. The bicycle according to claim 3,characterized in that said locking device (40, 43-46) is a mechanicalpositive-locking or frictionally-engaging fixing device.
 10. The bicycleaccording to one of claims 1 to 9, characterized in that one shut-offdevice (15, 16) each is positioned in both pressurizing medium lines(12, 13).
 11. The bicycle according to claim 10, characterized in thatsaid two shut-off devices (15, 16) can be actuated by a common actuator.12. The bicycle according to one of claims 1 to 11, characterized inthat said pressurizing medium lines (12, 13) are at least in sectionsarranged in the interior of said frame (1).
 13. The bicycle according toone of claims 1 to 12, characterized in that said front wheel suspensionand/or said rear wheel suspension comprises a resilient spring element(20, 49) for the additional cushioning of impact forces.
 14. The bicycleaccording to one of claims 1 to 13, characterized in that saidpiston/cylinder assembly (9, 14) of said front wheel and/or said rearwheel suspension forms a spring element.
 15. The bicycle according toclaim 13, characterized in that said spring element (20, 49) is amechanical compression spring.
 16. The bicycle according to claim 13,characterized in that said spring element (20, 49) is an element ofelastomer material or a steel spring or a separate compressed-aircylinder.
 17. The bicycle according to one of claims 13 to 16,characterized in that said spring element (20, 49) is arranged in acylinder chamber (34) of said piston/cylinder assembly (9) of said frontwheel suspension or of said rear wheel suspension, respectively.
 18. Thebicycle according to claim 18, characterized in that said spring elementis formed solely by said piston/cylinder assembly (9, 14) of said frontwheel or rear wheel suspension, respectively.
 19. The bicycle accordingto one of claims 13, 15 to 17, characterized in that said spring element(20, 49) of said front wheel suspension or said rear wheel suspension,respectively, is arranged outside the allocated piston/cylinder assembly(9, 14).
 20. The bicycle according to one of claims 1 to 19,characterized in that at least one filling valve (12″) is provided forfilling said first or second cylinder chambers (33-35, 41, 42),respectively, and said allocated pressurizing medium line (12, 13). 21.The bicycle according to one of claims 1 to 20, characterized in thatsaid two pressurizing medium lines (12, 13) can be connected with oneanother via a further pressurizing medium line (12′) and a furthershut-off device (15′).
 22. The bicycle according to claims 20 or 21,characterized in that a compressed-air reservoir is provided for fillingsaid cylinder chambers (33-35, 41, 42) via the filling valve.
 23. Thebicycle according to claim 22, characterized in that said compressed-airreservoir is integrated into the frame.
 24. The bicycle according to oneof claims 20 to 23, characterized in that a compressed-air generator isprovided for filling said cylinder chambers (33-35, 41, 42) or saidcompressed-air reservoir, respectively.
 25. The bicycle according toclaim 24, characterized in that said compressed-air generator isarranged such that it can be actuated by springing in of said frontwheel and/or said rear wheel suspension.
 26. The bicycle according toone of claims 1 to 25, characterized in that a fork that is rotatablymounted in the frame is provided, at least one of the respective forkarms of which is formed by a piston/cylinder assembly (9).
 27. Thebicycle according to one of claims 1 to 26, characterized in that aswing arm rear suspension (23) is provided which is flexibly connectedwith said frame (1) via a lag hinge (28) and said piston/cylinderassembly (14) of the rear wheel, wherein said piston/cylinder assemblyof said rear wheel suspension is provided for adjusting the pivotingangle between said swing arm rear suspension (23) and said frame (1).28. The bicycle according to claim 27, characterized in that a swingingspring element (20) is arranged between a lag hinge (22) that isprovided at said swing arm rear suspension and a lag hinge (18) that isprovided at said frame (1).
 29. The bicycle according to one of claims 1to 28, characterized in that said first and second cylinder chambers(34, 35, 41, 42) of at least one of said piston/cylinder assemblies (9,14) are connected with one another via a pressurizing medium line and ashut-off device, wherein said at least one piston/cylinder assembly (9,14) can be adjusted by opening the shut-off device irrespective of saidother piston/cylinder assembly (9, 14).
 30. A bicycle comprising a frameand at least one adjusting device, in particular for adjusting theheight of the front wheel suspension, the rear wheel suspension, thesaddle or the steering stem, respectively, wherein said adjusting devicecomprises a double-acting piston/cylinder assembly with a first cylinderchamber and a second cylinder chamber, characterized in that said twocylinder chambers (33-35, 41, 42) can be connected with one another viaa fluid channel (55, 59).
 31. The bicycle according to claim 30, whereina piston rod (19) connected with a piston (31, 61) projects from thepiston/cylinder assembly (9, 14), characterized in that said fluidchannel (55, 59) is a passage opening provided in said piston (31, 61).32. The bicycle according to claims 30 or 31, characterized in that ashut-off device (15, 60, 84) is positioned in said fluid channel. 33.The bicycle according to claim 32, characterized in that said shut-offdevice (84) can be actuated via an actuator (86) that is spaced apartfrom said shut-off device (84).
 34. The bicycle according to claim 33,characterized in that said actuator (86) is arranged in the region ofthe handle bar (8).
 35. The bicycle according to one of claims 30 to 34,characterized in that a locking device (43-46, 65) is provided forlocking said the adjusting device.
 36. The bicycle according to claim35, characterized in that said locking device (43-46, 65) is adouble-acting hydraulic cylinder with two cylinder chambers (43, 44)that are separated from each other by a hydraulic piston (40) that isconnected with said piston rod (19), and that said hydraulic chambers(43, 44) of said hydraulic cylinder can be connected with one anothervia a hydraulic line (45) and a shut-off device (46) positioned in saidhydraulic line (45).
 37. The bicycle according to claim 36,characterized in that the piston areas of said hydraulic piston (40)allocated to said two cylinder chambers (43, 44) of said hydrauliccylinder are of equal size.
 38. The bicycle according to claim 36,characterized in that the piston areas of said hydraulic piston (40)allocated to said two cylinder chambers (43, 44) of said hydrauliccylinder are of different sizes, and that a compensation device isprovided for compensating a difference volume flow between said twocylinder chambers (43, 44), which occurs during the shifting of saidhydraulic piston (40).
 39. The bicycle according to claim 38,characterized in that said compensation device is a compensationreservoir (66) that is connected with one of said two cylinder chambers(43, 44) via a fluid line.
 40. The bicycle according to claim 38,characterized in that said compensation device comprises a springpre-stressed shiftable compensation piston (88).
 41. The bicycleaccording to one of claims 35 to 40, characterized in that saidadjusting device and said locking device (43-46, 65) have a commonhousing (38).
 42. The bicycle according to one of claims 30 to 41,characterized in that said adjusting device is connected with aspring/damping element (20).
 43. The bicycle according to claim 42,characterized in that said adjusting device and said spring/dampingelement (20) are flexibly connected with one another.
 44. The bicycleaccording to claim 43, characterized in that said adjusting device andsaid spring/damping element (20) are arranged relative to each othersuch that the longitudinal axes of said adjusting device and of saidspring/damping element are crossing one another.
 45. The bicycleaccording to one of claims 30 to 44, characterized in that saidadjusting device is an integral component of a front fork (6).
 46. Thebicycle according to one of claims 30 to 45, characterized in that saidadjusting device is flexibly connected with a frame part (4) and a swingarm rear suspension (23) of the bicycle.
 47. A bicycle comprising aframe and at least one adjusting device, in particular for adjusting theheight of the saddle or the steering stem, respectively, wherein saidadjusting device comprises a double-acting piston/cylinder assembly witha first cylinder chamber and a second cylinder chamber, which areseparated from each other by a piston, wherein the area of the pistonlimiting said first cylinder chamber is larger than the area of thepiston limiting said second cylinder chamber, characterized in that alocking device (46, 66, 81) is provided for locking the piston (78). 48.The bicycle according to claim 47, characterized in that said lockingdevice is a single-acting hydraulic cylinder (81) that is connected witha fluid reservoir (66) via a hydraulic line (82) and a check valve (46).49. The bicycle according to claims 47 or 48, characterized in that saidfirst cylinder chamber (79) is formed by a tube (3) of a bicycle frame,that said piston (78) comprises a piston rod (75) on which a saddle (3a) or a handle bar or steering stem, respectively, is mounted, and thatsaid piston rod (75) is shiftable in said tube (3).
 50. Bicycleadjusting device, in particular for adjusting the height of the frontwheel suspension, the rear wheel suspension, the saddle or the steeringstem, respectively, wherein the adjusting device comprises adouble-acting piston/cylinder assembly with a first cylinder chamber anda second cylinder chamber, characterized in that said two cylinderchambers (33-35, 41, 42) can be connected with one another via a fluidchannel (55, 59).
 51. Bicycle adjusting device, in particular foradjusting the height of the front wheel suspension, the rear wheelsuspension, the saddle or the steering stem, respectively, wherein theadjusting device comprises a double-acting piston/cylinder assembly witha first cylinder chamber and a second cylinder chamber, which areseparated from one another by a piston, wherein the area of the pistonlimiting said first cylinder chamber is larger than the area of thepiston limiting said second cylinder chamber, characterized in that alocking device (46, 66, 81) is provided for locking said piston.